Long-span bridge



Jan. 9 1923.

' 1,441,387; 0. A. P. TURNER.

LONG SPAN BRIDGE.

ORIGINAL FILED Jun/10. 1913.

3 SHEET$-SHEET l.

/7 7 /0 I w x X x? 20 C A? xi/o WlTNEsgfggjg A TTORNE Y Jan. 9, 1923.1,441,387.

0. A. P. TURNER.

LONG SPAN BRIDGE. ORIGINAL FILED JULYIO, HH-

3 SHEEIS-SHEETZ 1N VEN TOR.

WITNESSES:

@ I mflm g B Jan. 9, 1923. 1,441,387.

0. A. P. TURNER.

LONG SPAN BRIDGE.

ORIGINAL FILED wuno, 1913. 3 SHEETS-SHEET 3.

INVENTOR.

WA TTORNEY.

CLAUDE a. rf'rnnnna; oriyunnnaroms, MINNESOTA, nssieivos or OLUMBUS,,OI-IIO. I

T0 tr. wnennnn,

I LONG-SPAN 'BRID GE.

Application filed July 10, 1 913,Seria1 No..'77 3,278. Renewed January21, 1921. Serial No. 439,058;

To all whomz't may concern;

Be it known that I, CLAUDE- A. P. TUnNnn, of Minneapolis, in the countyof Hennepin and in the State of Minnesota, have in? vented a certainnewand useful Improvement in Long-Span Bridges, and do here.-.

by declare that the following is a full, clear, and exact descriptionthereof.

My invention relates to'bridge trusses, and generally stated has for itsobject economy of material, and the production of a structure of greatstiffness. This application is filed as a renewal of application No.778,218, filed July 10, 1913, allowed Dec. 8, 1919,

and also to embrace a different embodiment.

the left and the top chord plan and bracing at the right; y i

Fig. 8 is a detail view in side elevation, showing the members of thecantilever frame extending between the top chord and the webbing- 1 Fig.4: is a view like Fig. 1 of. another embodiment of my invention.

Referring to the drawings, the truss shown comprises a top chord 10 anda bottom chord 11, and lVarren type webbing consisting of thediagonalmembers 12 and the sub-verticals 13 the panel points of the twochordsbeing located so that the bottom chord panels 1.2; 23; etc, are half aslong as the top chord panels AB; B C; etc. In the truss shown in thedrawings, which as I have stated is for a span of480 feet, the top chordpanels are feet and the bot tom chord panels are 4:0'feet', from whichdimensions an idea of the magnitude of the structure can be obtained.

At each side, of each topchord panel. point, a strut 14; extends betweenthe top chord and a diagonal member 12, inclining upward and outwardfrom the latter and between the lower ends of the two struts 1 1 ahorizontal strut 15 extends, these various parts being riveted together,as shown, so that it will be seen a frame work is provided that extendsaroundthe top chord panel. point, or the 3139);,33 a center,.bywhich thelength of the top chore section inclined struts 14: at a point 20 feetfrom the panel point. The frame work formed by the struts 1' 1 and 15 isindicated diagrammatically in Fig. 1 by the lines (Z, c, 7 and 'g.

It will be observed that each of the struts 14c and 15 acts incompression, the struts 14L being in sense cantilever arms and theintermediate strut 15 sustaining the thrust of the arms.

It will be seen that as the struts 14 (corresponding to the members cl,6 and and g of Fig. 1) are comparativelyshort, secondary stresses in thetop chord sections due to stress in the diagonal members 13 of thewebbing stretching or elongating said diagonal members, are largelyeliminated. I

To stiffen the diagonal web members 12 I connect them above each lowerchord panel point by a horizontal brace, or tie 16 which opposes thetendency of said diagonal mem-' bers to bow outwards under load. I Thebraces 16, it will. be noted, alternate with the struts 15 of thecantilever frame and each, it will be noted, is joined to the web memberat a point that is a fraction of their height or the distance from chordto chord, which preferably is about a quarter thereof- The floor plan,as shown at the left of Fig. 2, includes floorbeams 17 laterals 18 andstringers 19, and the top chord bracing,

loads, that is taken up by 'fiexure in all the members meeting at theapex. I

Referring to what is shown in Fi 4: which illustrates a design'for aspan til feet centers, the struts, 140, corresponding with the inclinedstruts, 14: of Fig. 1 ex tend from a point on the top chord, 100 midwaybetween the panel points-and to the diagonal, 120, of the webbing atampoint to alternate panels. The arrangement illustrated in Fig, 4 worksout very economically of material in practice.

Bymy invention a truss as provided that uses a minium of material it hasgreat stiffness and it eliminates, or greatly reduces secondarystresses.

Having thus described my invention what I claim is 1. In a bridge tr es,the combination of top and bottom chords webbing connecting the twochords that comprises diagonal members that meet in an apex at the topchord and a frame comprising struts constituting compression memberswhich eX-' tend from points on the top chord on opposite sides of saidapex downward'to said. diagonal members and supporting respectively theportions of the top chord to which they extend which lies between thesupported extremities of said portions of the top chord, said frameincluding a compression member extending between said diagr nal membersat the points where the lower ends olt said top chord engaging membersoin said. diagonal members.

2. In. abridge truss, the combination of top and bottom chords, webbingconnecting the two chords that comprises diagonal members that meet inanapex at the top chord and a frame at alternate panels comprisingstruts constituting compression members which'extend from points on thetop chord on opposite sides of said apex downward to said diagonalmembers and supporting respectively the portion of the top chord towhich they extend which lies between the supported extremities of saidportion of the top chord, said framevincluding a compression memberextending between said diagonal members at the points where the lowerends of said top chord engaging members join said diagonalmembers.

In testimony that I claim the foregoing I have hereunto set my hand.

' CLAUDE A. P. TURNER.

Vitnesses o CHAS. J. WVILLIAMsoN, A; T. IilAYES.

